1. Field of Invention
The present invention relates to a liquid crystal device, a driving method of the liquid crystal device, and an electronic apparatus.
2. Description of Related Art
There are two types of liquid crystal alignment modes: a twisted nematic (hereinafter referred to as TN) mode, in which the liquid crystal molecules are, in the voltage OFF state, aligned substantially parallel to a substrate and twisted towards a direction perpendicular to the substrate, and a vertical, or homeotropic alignment mode, in which the liquid crystal molecules are vertically aligned. The TN mode has been used in the related art because of high reliability; however, much attention has been recently focused on liquid crystal devices using the homeotropic alignment mode due to several excellent characteristics.
For example, in the homeotropic alignment mode, the state where the liquid crystal molecules are perpendicularly aligned relative to the substrate, that is, no optical retardation exists from the normal direction of the substrate, is used as a black display state. As a result, high quality black display and high contrast are obtained. In addition, since liquid crystal display devices operated in the homeotropic alignment mode have better contrast characteristics from the front view, the range of viewing angles with a constant contrast becomes wider compared to TN liquid crystal displays, which are operated in a homogeneous alignment mode.
Unfortunately, in the homeotropic alignment mode, the tilt direction of the liquid crystal must be appropriately controlled. Otherwise, disclination, which is a region where the liquid crystal molecules do not fall, occurs in the center of the dot area, thus disadvantageously decreasing brightness of the display. Additionally, the liquid crystal molecules fallen radially about the disclination change the angle of the director of the liquid crystal molecules with respect to the polarizer in the dot areas, so that the amount of light passing through the polarizer is disadvantageously decreased.
To overcome these disadvantages of the liquid crystal display in the homeotropic alignment mode, Japanese Unexamined Patent Application Publication No. 11-212053 indicated below, for example, discloses a liquid crystal display device that controls the tilt direction of the liquid crystal molecules in the voltage ON state by mounting embedded electrodes to control the alignment in the boundary areas of pixel electrodes, which are arranged on a substrate in a matrix in plan view.
According to the liquid crystal display device disclosed in the above-described Japanese Unexamined Patent Application Publication No. 11-212053, the embedded electrodes, which are controlled independently from the voltages applied to pixel electrodes, can control a tilt direction of liquid crystal molecules in dot areas when voltage is applied. However, since the embedded electrodes are disposed between pixel electrodes and substrates, the embedded electrodes must generate a stronger electric field than that generated by the pixel electrodes to appropriately control the direction. That is, a higher voltage must be applied to the embedded electrodes than to the pixel electrodes and so the driving circuit of the embedded electrodes must have a high withstanding voltage. Consequently, the complicated structure and the required high quality of the circuit disadvantageously make the fabrication difficult and costly.